Military activities in marine environments (i.e., training and demilitarization) have resulted in munitions and unexploded ordnance being located throughout the world's oceans, yet the ecological impacts to marine life from the associated chemical constituents and their breakdown products remains largely unknown. Coral reefs are particularly vulnerable ecosystems found in proximity to many key U.S. military installations in the Caribbean and Pacific Islands. The impact on the health and reproductive fitness of local coral populations incurred by exposures and the ecological risks that exposure poses to corals and reef connectivity across ocean basins will be investigated in this project. Such information is relevant to Department of Defense (DoD) management decisions in balancing continuity of operations with environmental compliance and stewardship.
The objectives of this project are to evaluate whether munitions compounds (MCs)–TNT, RDX, PETN, and HMX–or their breakdown products impact corals and determine the ecological risk they may pose to coral and coral reef health.
Toxicity reference values will be generated from munitions-contaminant exposure profiles for two coral species using laboratory-based coral cell toxicity assays to determine concentration ranges for observed effects. Reference and MC field sites co-located with coral reefs will be assessed to determine if the field conditions create a toxic environment to corals and which chemical(s) are responsible for the toxicity. Pore water toxicity assays (using two primary coral cell types from two species) and toxicity identification evaluations will be used in assessing if MCs on reefs present a coral health problem. Analytical chemistry methods (GC-MS, LC-MS) will be used to identify and measure specific chemicals of concern in sediments, pore waters, and coral tissues. Biological effects will be characterized by a combination of laboratory and field studies, which measure cellular, tissue, and organismal-level parameters that are diagnostic for pathological endpoints (especially endpoints associated with reproductive viability and effort). Reference populations will be used to establish nominal ranges for each endpoint. Field-determined MCs of concern will be used in follow-up laboratory exposure studies of intact symbiotic coral fragments, i.e., nubbins (receptor model), to determine their effect on intact coral versus coral cells (coral cell toxicity assay) and establish whole animal toxicity reference values. Data from field and laboratory studies will be used to develop a risk characterization model that describes the health risk of exposure to MCs using coral with their symbiotic algae, Symbiodinium, as ecological receptors and identifies high- or low-risk situations for use in management decisions.
This project will establish toxicity reference values for corals exposed to MCs and describe risks to coral health associated with exposure to discarded or unexploded ordnance for use in a formal ecological risk assessment process. The screening (or action) values derived from this work will provide metrics for assessing (1) the risk of munitions to coral health and reproductive fitness for any location and (2) remediation efforts addressing any identified risks. This project will also provide improved, cost-effective field monitoring techniques to screen for potential environmental impacts on corals or coral reefs, prior to initiating more costly analytical investigations. (Anticipated Project Completion - 2015)